title: Mechanism of cadmium induced apoptosis in human peripheral blood lymphocytes: the role of p53, Fas and Caspase-3.
abstract: Cadmium (Cd) is a major pollutant of environment. It can be fatal to human. In spite of bulk of research and literatures, the mechanism of a fatality against human is still not understood completely. Toxic and carcinogenic effects of Cd in rodents and humans are well known. However, effects of Cd on induction of apoptosis are still elusive. This study indicates immunosuppression and immunotoxicity due to Cd exposure. Present study was undertaken to determine the mechanism of cell death in vitro in human peripheral blood lymphocytes induced by Cd. Our findings suggest the toxicity due to Cd is attributed to programmed cell death-apoptosis. IC₅₀ was calculated at 21.74 μM. A significant increase of expression of the pro-apoptotic genep53, Fas and Caspase-3 in human lymphocytes was found. Cd induced p53-dependent apoptosis through cooperation between Bak upregulation without changing the Bcl-2 and Bax expression. Data of this study compel to speculate that apoptosis may also be attributed to CD95/Fas complex formation, and p53 direct apoptogenic potential at mitochondria. It was confirmed by the increased expression of Caspase-3. Although, this work does not address all the questions regarding the mechanism of Cd induced apoptosis, but these findings establish an important role of p53 and mitochondrial function during apoptosis in human lymphocyte. Moreover, based upon our findings, the role of Fas in Cd induced apoptosis is also undeniable. Hence further investigations are required to understand the different mechanism involved into apoptosis of lymphocytes due to Cd exposure.
authors.affiliation: Molecular Cancer Biology Research Lab. (MCBRL), Department of Food Science and Nutrition, College of Food and Agricultural Sciences, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Abdullah H
authors.initials: AH
authors.lastname: Al-Assaf
authors.forename: Ali M
authors.initials: AM
authors.lastname: Alqahtani
authors.forename: Ali A
authors.initials: AA
authors.lastname: Alshatwi
authors.forename: Naveed A
authors.initials: NA
authors.lastname: Syed
authors.forename: Gowhar
authors.initials: G
authors.lastname: Shafi
authors.forename: Tarique N
authors.initials: TN
authors.lastname: Hasan
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002104:Cadmium / Q000097:blood / Q000633:toxicity*; D053148:Caspase 3 / Q000187:drug effects / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects; D004396:Coloring Agents; D053938:DNA Fragmentation / Q000187:drug effects; D006801:Humans; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000187:drug effects* / Q000201:enzymology; D060888:Real-Time Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D014158:Transcription, Genetic / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects / Q000502:physiology*; D019014:fas Receptor / Q000187:drug effects / Q000502:physiology*
chemical_list: D004396:Coloring Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; D002104:Cadmium; D053148:Caspase 3; C022616:thiazolyl blue
keywords: Apoptosis; Cadmium; Human lymphocytes; Pro-apoptotic genes expression; Toxicity